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United States Patent 3,123,634 N-ALIPHATIC-N,N-DE(ALKYL MONGSUCCINATE) AMINE John H. Udelhofen, Calumet City, llL, assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Filed Apr. 28, 1961, Ser. No. 106,1% 3 Claims. (Cl. 260-485) This invention relates to chemical compounds and their use as rust inhibitors and corrosion inhibitors in normally liquid oleaginous compositions. This invention further relates to and provides normally liquid oleaginous compositions, especially in the presence of Water, inhibited against rust and corrosion by the inclusion therein of certain hydroxyamine esters of succinic acid provided herein.

In the handling and storage of many normally liquid hydrocarbons and hydrocarbon products, serious problems of corrosion are encountered particularly corrosion to ferrous metal parts. Under conditions of handling the storage of normally liquid hydrocarbons, Water often becomes included with the hydrocarbon through seepage, condensation or even from processing of the hydrocarbon. Also present in the hydrocarbon in many instances are acidic and/ or caustic substances in small amounts resulting from 'prior treatment of the hydrocarbons, e.g., from acid treating and/or caustic treating of fuel oils and lubricating oils. Such acidic and/or caustic materials are corrosive toward metal parts such as storage tank walls, valves, pipelines, tank car walls, burners, gasoline tanks, crankcases, etc. Other corrosive substances may be formed through oxidative deterioration of the hydrocarbon in the presence of oxygen particularly if the hydrocarbon is stored for substantial periods of time or stored or supported under adversely high temperature conditions. The water present in the hydrocarbon often causes the formation of two separate phases, i.e., a hydrocarbon phase and an aqueous phase. The corrosive materials become distributed throughout both the hydrocarbon and aqueous phases and it becomes desirable, if not necessary, to protect against corrosion of metal parts from both phases. The presence of the water phase also, of course, promotes rusting of metal parts such as tank walls, pipes, etc. The present invention provides normally liquid hydrocarbon compositions which have imparted thereto the ability to protect against rust and corrosion of both phases by the inclusion therein of certain corrosion inhibiting agents.

The compounds of this invention have the structural formula:

R R o H R-Ni:dH( )Hoi JoH2OHro0H 2 wherein R is an open-chain (non-cyclic) aliphatic hydrocarbon group containing from 8 to 22 carbon atoms and R and R" are selected from the class consisting of hydrogen, methyl and ethyl. R may be saturated, mono unsaturated, (ii-unsaturated or poly-unsaturated, preferably saturated, rnono-unsaturated or di-unsaturated.

In the preferred embodiments, R contains from 12 to 18 carbon atoms and R and R" are each hydrogen.

The compounds may be termed monoesters of succinic acid or diesters of an N,N-di(hydroxyall yl)-N-aliphatic amine but are more descriptively referred to herein as N-aliphatic-N,N-di(alkyl monosuccinate) amine or, more simply, as aliphaticaminoalkylsuccinates.

The aliphaticaminoalkylsuccinates may be used in accordance herewith in a normally liquid hydrocarbon in amounts sufficient to inhibit corrosion and more desirably in amounts sufficient to inhibit corrosion caused by the presence of water in a separate phase in contact Patented Mar. 3, 1964 'ice With the normally liquid hydrocarbon. More advantageously, the corrosion inhibitors may be used in amounts of from about 000005 to about 10 weight percent in a normally liquid hydrocarbon and preferably in amounts of about 0.0001 to about .01 weight percent. The salts, e.g., the amine salts and especially the substituted imidazolinium salts, of the a1iphaticaminoalkylsuccinates can also be prepared for use as effective corrosion inhibitors by reacting sufiicient substituted imidazoline therewith to neutralize one or both carboxylic acid groups.

The R group of the compounds apparently serves two functions. The hydrocarbon chain provides the property of oil-solubility and also provides a sufliciently thick mononuclear layer for the purpose of protecting metal surfaces against rust and corrosion.

More specific examples of compounds of this invention are listed below. For simplicity in nomenclature, the listed examples are identified with reference to the structural formula set out above by identification of the R, R and R" groups.

Example No. R R R Octadecyl Hydrogen.-. Hydrogen.

dol Methyl.

do. Ethyl. Methyl- Do. Hydroge Hydrogen. Ethyl Ethyl. Hydr0gen Hydrogen. I-Iexadecadienyl--. do Ethyl. Heptadecyl Methyl. Oleyl Hydrogen.

D0. Ethyl. Hydrogen.

Do. Do. Do. Do. Do. Do. Methyl.

Do. do Ethyl.

Myristyl Methyl. S0ybeau Do. Co Do. o thyl.

Soybean Hydrogen. Linolenyl Do. Dodeeadienyl. Do. Stearyl D0.

The designations coco, soybean and tallow are used to designate aliphatic groups derived from coco amines, soybean amines and tallow amines respectively. The coco, soybean and tallow amines are derived from the coconut fatty acids, soybean fatty acids and tallow fatty acids by reaction of the fatty acids with ammonia resulting in the formation of mixtures of amines having varying molecular Weights. The amines prepared from the fatty acids are available commercially from Armour & Company under the tradenarne Armeen. The Arrneens may advantageously he used as a source of primary aliphatic amines in preparing N,N-di(betahydroxyalkyl) N-aliphatic amines for use in preparing compounds of this invention. Examples of the Armeens are Armeen T (derived from tallow fatty acids and containing about 2% tetradecyl amine, 24% hexadecyl amine, 28% octadecyl amine and 46% octadecenyl amine) and Armeen 12 (containing 2% decyl amine, dodecyl amine and 3% tetradecyl amine). Other amines from which the ILN-di(beta-hydroxyalkyl) N-aliphatic amines may be derived are the Alamines marketed by General Mills such as Alamine 26 (a mixture of saturated, mono-unsaturated and (ii-unsaturated C primary amines) and Alamine 21D (distilled primary coco amine).

The compounds of this invention may be conveniently prepared by reacting one mole of the corresponding N,N-di(beta-hydroxyalkyl) N-aliphatic amine with tWo moles of succinic anhydride. The reaction may be conveniently carried out at normal esterification temperatures preferably in the range of 100200 C. or higher if desired. The reaction proceeds at a more rapid rate at higher temperatures and at a slower rate at lower temperatures. The reaction is terminated, e.g., by removal of heat upon completion of the desired esterification, 2 to 8 hours usually being sufllcient for completion of the reaction. Succinic acid may be used in lieu of the anhydride, if desired, but the anhydride is preferred. Where the acid is used in lieu of the anhydride, the water formed may be removed by distillation, but removal of water is not necessary where the anhydride is used.

The reactions in forming the compounds useful in this invention may conveniently be carried out using a solvent in the reaction medium. Useable solvents are the aromatic hydrocarbons and particularly the lower boiling hydrocarbons such as benzene, toluene, xylene, ethylbenzene and the like. It is usually not particularly desirable to remove the solvent after the reaction, especially where the solvent is an aromatic hydrocarbon which may be permitted to be incorporated into the normally liquid hydrocarbon to which the aliphaticaminoalkylsuccinates are added. The lower boiling aromatic hydrocarbons are preferred because they boil within the most desirable reaction temperature ranges. The solvents may function in controlling reaction temperature in that the reaction may be carried out at the reflux temperature of the solvent.

The N,N-di(beta-hydroxyalkyl) N-aliphatic amines may be prepared by the reaction of two moles of the corre sponding alkylene oxide with one mole of the corresponding primary aliphatic amine. The alkylene oxide-primary amine reaction is well known to the art. Useable alkylene oxides, for example, are ethylene oxide, propylene oxide, butylene oxide, etc. Examples of useable primary amines are the amines having the formula RNH wherein R is as identified above. These include, as more specific examples, all of the primary amines having R as specifically identified in the table of examples set out above.

As a typical preparation of an aliphaticaminoalkylsuccinate, 18.60 grams of bis-(beta-hydroxyethyl)-octadecylamine dissolved in 200 ml. of benzene were added slowly with stirring to 10.00 grams of succinic anhydride in 100 ml. of benzene. The mixture was refluxed for four hours. The solvent was removed by vacuum distillation leaving 28 grams of N-octadecyl-N,N-di(ethyl monosuccinate) amine, having the formula:

olnoHzothornomiiorr CisHa7N as a viscous liquid product.

The normally liquid hydrocarbons include those hydrocarbons boiling in the gasoline through lubricating oil range and preferably those normally liquid hydrocarbons boiling in the gasoline distillation range. Examples of normally liquid hydrocarbons are gasoline, heater oil, jet fuel, kerosene, mineral lubricating oils, synthetic hydrocarbon lubricating oils, furnace oils, residual heating oils, fuel oil blends containing residual and distillate fuel oils, e.g., Bunker C, gas oils and other residual and distillate fuel oils. The normally liquid hydrocarbons may contain other non-hydrocarbon components, e.g., sulfur, normally present in diesel fuels. The lubricating oils may be sulfur extracted if desired. The normally liquid hydrocarbons may be virgin hydrocarbons or may be processed, e.g., by cracking, alkylation, reforming, isomerization and the like. The rust inhibitors of this invention are believed to be especially effective in petroleum hydrocarbons and their preferred use is in combination with normally liquid hydrocarbons boiling in the gasoline distillation range.

In order to illustrate the rust and corrosion inhibition properties of the compositions of this invention, examples of compositions of this invention were prepared and subjected to rust and corrosion test as follows:

Indiana conductometric rust test (static).This test tests for corrosion inhibition and rust inhibition properties in the presence of corrosive acidic and caustic substances. The test was run using the hydrocarbon phases as identified in the table below. In accordance with the procedure of the test, samples of 0.00073 weight percent (2 pounds per thousand barrels) of N-octadecyl-N,N-di(ethyl monosuccinate) amine, the compound identified as Example 1, above, in the hydrocarbon phase identified in the table below were prepared. Each sample was placed with an equal volume of water containing added caustic and/or acidic substances in a test tube and stirred briefly to permit the addition agent to become distributed within both the hydrocarbon and aqueous phases. An S-shaped steel test strip, having an electrical terminal at each end of the S was immersed in the hydrocarbon phase to reach adsorption equilibrium and the electrical resistance is noted as a control resistance value. The steel strip was then lowered into the aqueous phase and after 24 hours the change in electrical resistance was taken as a measure of rusting and corrosion in both the aqueous and hydrocarbon phases during the 24-hour period. A determination of rusting and corrosion inhibition was made in terms of corrosion rate measured in mils penetration per day times 10 The mils penetration per day were converted to percent reduction in corrosion by the following equation:

X =poreent reduction in corrosion r =corrosion rate of steel strip in fuel with inhibitor. r =corrosion rate of steel strip in fuel with no inhibitor.

The percent reduction in corrosion is reported in the following table:

The data of the table indicate the ability of the compositions of this invention to inhibit rust and corrosion even in concentrations lower than .0008 weight percent. In comparison with the control (containing no additive) the compositions of this invention demonstrated an excellent ability in inhibiting rust and corrosion in both the aqueous and hydrocarbon phases in the presence of water and under caustic and acidic conditions.

It is evident from the foregoing that I have provided compounds useful in normally liquid hydrocarbon oils for the prevention of rust and/ or corrosion.

I claim:

1. As a composition of matter, the compound having the structural formula:

wherein R is an open-chain aliphatic hydrocarbon group having 8 to 22 carbon atoms and R and R" are selected from the class consisting of hydrogen, methyl and ethyl.

2. The compound of claim 1 wherein R has from 12 to 18 carbon atoms and R and R" are both hydrogen.

3. As a composition matter, the compound having the structural formula:

References Cited in the file of this patent UNITED STATES PATENTS Kritchevsky Oct. 5, Katzman et a1. Sept. 19, Caldwell Apr. 6, Steadman et a1. Apr. 8, Payne et a1. Apr. 29, Newman et a1. July 8, Verdol July 5, Nygaard May 2, 

1. AS A COMPOSITION OF MATTER, THE COMPOUND HAVING THE STRUCTURAL FORMULA: 